The catalysts of this invention comprise catalytic metals held within synthetically layered clays having synthetic high temperature stable pillars separating the layers of clays. This acts to selectively sandwich the catalytic metals. In 1979, U.S. Pat. No. 4,176,090 issued to Vaughan et al relating to a stable pillared interlayered clay composition arrived at by reacting smectite type clays with polymeric cationic hydroxy metal complexes. See also U.S. Pat. Nos. 4,271,043 and 4,248,739. A specific example of a polymeric cationic hydroxide metal complex is aluminum chlorohydroxide. After preparation, the sandwiched layers are spaced by a distance of 9 to 12 angstroms having high temperature stable pillars so that the particular interlayered clay can be used in high temperature reactions such as catalytic cracking, hydrocracking, hydrotreating, isomerization, and reforming, etc. without undo depreciation. The interlayered clays are also disclosed as molecular sieve absorbents. In the examples of this patent, the prepared interlayered clays are shown to possess advantageous hydrocracking activities with improved hydrothermal stability. The absorptive qualities of the pillared interlayered clays are also demonstrated.
Montmorillonites crosslinked with aluminum hydroxide or chromium hydroxide are disclosed as molecular sieves in U.S. Pat. No. 4,216,188, issued to Shabria et al. The presence of a reactive structural hydroxide group on the surface of the crosslinking component is taught as being particularly significant in regard to an increase in catalytic activity in esterification rates. In U.S. Pat. No. 4,238,364, issued in 1980 to Shabtai, a molecular sieve cracking catalyst is prepared by partially crosslinking smectites with hydrogen or rare-earth elements. One contemplated conversion using this catalyst is modification of heavy liquids, such as native black oils and petroleum resids to distillate products such as gasoline. In Examples 3 and 4, a catalytic cracking process is exemplified wherein 1-isopropylnaphthalene is converted to another hydrocarbon material at a rate approaching 5 to 6 times the conversion rate obtained utilizing a stabilizing HY-type zeolite.
In Elattar, U.S. Pat. No. 4,515,901, an interlayered pillared clay is formed utilizing a soluble carbohydrate and a soluble pillaring agent. The pillaring agent is preferably a metal or organometallic compound which is soluble in water, alcohol or another polar solvent. Useful carbohydrates include simple carbohydrates such as monosaccharides and oligosaccharides. The advantage of this invention is that the carbohydrate is eliminated during heating and is not necessary to the proper functioning of a pillard interlayered clay as it performs its catalytic support function. Use of the prepared catalyst is shown in a process for the production of alcohols from carbon monoxide and hydrogen. In Jacobs et al, U.S. Pat. No. 4,436,832, issued in 1984, a process is set forth for the preparation of bridged clays suitable as catalysts or catalyst supports for the conversion of paraffins or olefinic hydrocarbons, wherein the clay suspension is subjected to dialysis during preparation. Example 5 exemplifies a process for hydroisomerization and hydrocracking of normal decane to more volatile hydrocarbons. In Gregory et al, U.S. Pat. No. 4,531,014, a process is described utilizing a cation-exchangeable clay for the conversion of aliphatic linear olefins to a product comprising a hydrocarbon having a higher carbon number such as dimers, oligomers, etc.
Recognition has been made in U.S. Pat. No. 4,510,257, assigned to the assignee of interest herein, that intercalated clays can be selectively used to crack hydrocarbons as a derivative of the relatively large angstrom size separating the pillared clay layers. The specific catalytic cracking embodiment demonstrates that a silicon pillared cerium bentonite catalyst possesses cracking activity for a hydrotreated light catalytic cracking feed.
The above references depict many methods of preparation of the interlayered pillared clay material. Recognition has also been made that such interlayers may advantageously be used as a molecular sieve or for catalytic reaction purposes. There has, however, been no recognition that catalytic hydroconversion, inclusive of aromatic hydrogenation and catalytic cracking, can be selectively achieved to crack tricyclic compounds, in preference to other compounds present in a middle distillate fuel such as decalins, tetralins, paraffins and isoparaffins.